水酸化エニンのプラチナ・金触媒サイクロアイソメリゼーション反応
Victor Mamane1, Tobias Gress, Helga Krause
1Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany.
Journal of the American Chemical Society
|July 15, 2004
まとめ
プラチナとゴールドの触媒は,水酸化エニンを選択的にバイサイクロ[3.1.0]ヘキサン-3-オンの誘導体に再配置します. この新しい骨格の再編成は,サービノーンとサービノールの合成に適用されました.
科学分野:
- 有機化学 オーガニック・ケミストリー
- カタリシス カタリシス カタリシス
- 合成方法論 合成方法論
背景:
- 水酸化エニンは,有機合成における多用途の基質である.
- 触媒的再配置は,複雑な分子構造への効率的な経路を提供します.
研究 の 目的:
- 水酸化エニンの新しい触媒的再配置を開発する.
- ビサイクロ[3.1.0]ヘクサン-3-オンの誘導体および関連化合物を合成する.
- この方法論を自然製品の総合合成に適用する.
主な方法:
- PtCl2または (PPh3) AuCl/AgSbF6.6を使用した触媒的再配置.
- プラチナ触媒によるアリレーションとサイクロアイソメリゼーションを含むワンポット合成.
- デウテリウムラベル付けと立体化学分析.
主要な成果:
- 水酸化エニンからバイサイクロ[3.1.0]ヘクサン-3-オンの誘導体の選択的形成.
- 開発した方法論を用いて,サビノンとサビノールの合成が成功しました.
- アセテット中介物質とゴールドカタリシス経由で,同位体バイシクロ[3.1.0]ヘクサンの誘導体へのアクセス.
- サイクロプロピルメチルプラチナカルベンの中間物質の識別.
結論:
- 水酸化エニンの新しく効率的な触媒的骨格再構成が確立されました.
- この方法は,貴重なバイサイクル化合物やテルペンの簡潔なアクセスを提供します.
- 機械学的洞察は,サイクロプロピルメチルプラチナカルベンの中間物質の関与を支持する.
関連する概念動画
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
03:00Preparation of Epoxides
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
01:18Reactivity of Enols
Enols are a class of compounds where a hydroxyl group is attached to a carbon–carbon double bond, which implies that it is a vinyl alcohol. A carbonyl compound with an α hydrogen undergoes keto–enol tautomerism and remains in equilibrium with its tautomer, the enol form. Usually, the keto tautomer is present in a higher concentration than the enol tautomer due to the higher bond energy of C=O compared to C=C. Moreover, the direction of the keto–enol equilibrium is governed by factors like...